Performance characteristics of plant produced high RAP mixtures

TLDR

The study aimed to produce plant‑generated Reclaimed Asphalt Pavement mixtures, document their production parameters, and assess how virgin and RAP binders blend. Eighteen mixtures (0–40 % RAP) were produced at three Northeast sites using softer binders, and their stiffness, cracking, rutting, moisture susceptibility, and workability were evaluated under varying production conditions. Results showed that blending behavior depends on production parameters; stiffness rose with RAP content unless discharge temperatures varied, cracking resistance fell, while rutting and moisture resistance improved, and laboratory reheating further increased stiffness.

Abstract

The main focus of this study was to obtain plant produced Reclaimed Asphalt Pavement (RAP) mixtures, to document the mixture production parameters and to evaluate the degree of blending between the virgin and RAP binders. The effect of mixture production parameters on the performance (in terms of stiffness, cracking, rutting, and moisture susceptibility) and workability of the mixtures was evaluated. Eighteen plant produced mixtures were obtained from three locations in the Northeast United States. RAP contents (zero to 40%) were varied and softer binders were used. The data and analysis illustrated that the degree of blending between RAP and virgin binders is a function of production parameters. The stiffness of the mixtures increased as the percentage of RAP increased, but not when the discharge temperatures of the mixtures were inconsistent. The cracking resistance was reduced as the percentage of RAP increased. The rutting and moisture damage resistance improved as the percentage of RAP in the mixtures increased. Finally, reheating the mixtures in the laboratory caused a significant increase in the stiffness of the mixtures.